Rtools45

Dear R Windows developers,

there is now a new toolchain for R for Windows, Rtools45. It is now used 
by R-devel and R 4.5.0 (now alpha).

Compared to Rtools44, it uses GCC 14 and updates other core components. 
See https://cran.r-project.org/bin/windows/Rtools/rtools45/news.html for 
a detailed list of changes. All users of R-devel who need to compile R 
packages with source code in C, C++ or Fortran should install Rtools45. 
 From the user perspective, Rtools45 works the same way as Rtools44.

See https://cran.r-project.org/bin/windows/base/howto-R-devel.html for 
instructions on how to build R-devel and packages for that version of R.

See https://cran.r-project.org/bin/windows/base/howto-R-4.5.html for 
instructions how to build R 4.5.0 and packages for that version of R.

It is recommended to re-install packages that need compilation to avoid 
potential incompatibilities with code built using Rtools44.

Rtools45 includes an experimental version for 64-bit ARM (aarch64) 
machines, using LLVM 19 (and clang, flang-new, lld, libc++). The aarch64 
version of Rtools has its own installer and distribution tarballs.

Best
Tomas